Cinematographic apparatus



Nov. 20, 1928. Y

' E. ol-:HMlcHEN CIEMATOGRAPHIC APPARATUS Filed Dec. 51, 1926 2 sheds-sheet 1 Nov. 20, 1928.

: 1,692,092- E. oEHMlcHEN f CINEMATOGRAPHIC APPARATUS Filled nec. v31. 192e 2 sheets-sheet 2 4/A/z/fA/'Tal/Q y f. @ehm/chen.' y W f7. M wf.

' tusv Patented Nov. 20, 119,28.

V UNITED STATES yIEFLIIIN'INE4 OEHHICHEN, 0F VALENTIGNEY, FRANCE.

CINEHATOGBAPHIC APPARATUS.

Application nled December 31, 1926, Serial No. 158,297, and in France November t5, 1926. v

In' all cases, the known types of cinematographic apparatus for view taking or projection uti i'ze pressing elements, usually controlledby springs, for constantly applying I the film'against its guideway.

This arrangement assuresthe fiat position' 1li its orward travel must be great, thus resulting in a rapid deterioration of the perfora tions inthe film and also of the teeth of the driving device, with a consequent wear of z the film 'and of the apparatus at the samel time.

With the use of s ecial films', consisting of a substance other t an celluloid, which are -weaker 'or thinner than the usual films, 1t

L may prove impossible to dispose the films.' in the normal apparatus, even when reducing the pressureof the said springs to the extreme limits'.

My invention -relates`to cinematographic Iapparatus in which the ressure -elements are controlled by means o a device which is automatically 'actuated by the mechanism of the cinematographic apparatus, so as to prod ucethe full pressure onthe film when it is stopped, and to remove the pressure during l. the whole or a kI'Jait of the travel of the film. t Y

According -to my invention, thel mecha- "nism for the periodic pressing yforms a complete device together with the gate, which can 'be readily adapted to the usual apparaa very simple transformation, thus ,enab ing theintouse films of all kinds in j conditions" iny which the film will be subject to less strain and wear,

' l45' The appended drawings `show way of inven-V example -,various embodiments of i F" `.1f'"12,13 and 4 show various controls '-for-t "e" push rod with variable pressure'.`

sof 'Figa- 5, 6, an 'l' are perspective ,views showing doors which are entirely fitted outl and enable the present invention to be emr' ployed with the known cinematographic apparatus.

In Fi 1, 1 is the film which'travels be- 55 tween t e wall 2 of the guideway landrone of the principal shoes which is urged by the spring 4. Y

A power transmission device connected with the mechanism of the'cinematographic 60 apparatus actuates by means of a cam 5 (or an eccentric or like member) a 4set of levers 6-'7 acting upon the rod 8 ofthe shoe 3 so that the latter will exercise itsaction when the film is stopped and will be separated 05 from the wall 2 when the film travels.`

A pressure element 9 controlled by permanently acting springs 10, may be disposed preferably at the input vend of the guide- Way. The said pressure element is so reg- 7 ulated as to exercise upon the film the exact pressure required to assure a constant con'- tact between the teeth of the Hlm-actuating device 11 and the co-operating edges ofthe film perforations. However, the pressure due. to the said element 9 is not sufficient to flatten the film, this being obtained by .the device for intermittent pressure which yis controlled by the mechanism. As will be observed,the film is left free by the main 80 vpressing device 3 when it travels forward, and the additional pressing element 9 whose action is very sli ht will simply assure'the uniform travel o the film. v i

The element 9 must be suitably adjusted 85 as to its pressure, according to the nature of the film em loyed. f It should be noted that a light lm, which is consecuently weaker, will have a small inertia and will hence require less pressure to prevent it 9o from passing beyond the teeth' when the latter are stopped.' Y

Obviouslynnyl invention does not depend upon the method of power tranenission employed to assure the. riodic'motion of the o5 pressing device, and may utilize'varioua means producing the same result, such as pneumatic elements comprising closed expansion chambers or pistons, electromagneticdevices controlled by rotating or like of its movement, and to pressit to the maximum during the stoppingperiod.-

I mayremploy various devices for thisv purpose.

For example the pressing devices may be reduced to a single one, or on the contrary their number may be increased.

' In -the cease in which a single element is employed, the device is constructed as shown' in Fig. 2. The push rod 8, controlled by the strong spring 4, acts periodically upon a shoe 3 (or a frame) which is permanently urged by one or more springs 10 whichare very weak and are only sufficient to produce the braking effect necessary to hold the film.'

The actuating device directly controls the push rod 8 so that its pressure is added to that of the springs 10 when the maximum pressure on the shoe is to be obtained, and that the action of the pressing element can be eliminated or reduced during the other parts of the period.

Obviously, the said actuating device may be employed without the intermediary of kthe shoes or like pressing devices. Fig. 3

shows a construction of this kir'l, in which the rod 8 of the shoe is conn Ved with its control lever 7 by means of an elastic member 4. Imay even eliminate this member if the device 6-7 has a sufcint elasticity.

For the indirect control, which is usually employed, two distinct arrangements may be provided, as follows.

In the first arrangement (Fig. 4) the leverv 7 acts upon a grooved sleeve 12 which is slidable on the'push rod 8; the spring 4 is placed between the said sleeve and a disc 13 secured to the said rod. By the use-of the pin 14, the said rod can be moved backward by the said sleeve.

The spring 4 normall urges the rod- 8 against the shoe 3, and t e actuating mechanism 6-7 acts in such manner as to reduce the effect of the spring 4, and then to draw back the push rod itself at a certain point in the functioning of the said mechanism. I thus obtain a progressive action, and the whole effect is produced as if the tension of the sprin were regularly diminished vor increased in order to obtain the back motion ofdthe push rod,or the pressure of the said ro In the second arrangement Fig. 2), instead of varying the tensin o the spring 4, I directly control the ush rod 8 in such manner that assoon ast e mechanism acts,

the said shoe willbe released and the pres sure eliminated in an abrupt manner.

It may be advantageous to entirely remove the pressure during the functioning, except for a very short instant before each stop, and herein I may so dispose the apparatus that the intermittent device contro led by the mechanism will also effect the slight pressure at 9 for the tension of the film. The said pressing device will thus be raised during the major part'of the travel, and it will be again applied against thelm for only a very short time before the end of the travel of the film, thus giving the film a slight tension whichY is just sufiicient for a regular succession of the images. By thus reducing the duration .of the pressure to the minimum, I am enabled to reduce the wear of the film perforations.

In these conditions, lthe duration of the stress of the teeth upon the film is reduced to the minimum and the resulting wear isv diminished. l

The improvements according to my .1n-

vention consist more particularly in the use of an intermittent -pressing mechanism which forms with the guideway a complete device which may be employed with the` known cinematographic apparatus whereby they will be enabled to `utilize all types of films -in approved conditions of minimum wear.-

Figs. 5 and 6 show such a constructlon, which is characterizedby the use of a special door 15 in which the axle of the hinge forms the drivin shaft for the various movements contro ling the two push rods film.

Upon the shaft 16 are mounted the .actuatin elements such as the levers 21 (Fig. 5)

or t e cams 22 (Fig. 6), acting upon the pressing members or upon the elastic means controlling said members which are mounted on the door itself. The said door, its pivot shaft, the hinge pieces 23 and the cam shaft 17, will constitute a. combined deYie which iis la closed at all times during the travel of the may beplaced at `once upon a known appa- Y ratus and may be substituted for thel usual` door with great facility: in 4this manner .an apparatus adapted for the usual film can be converted into an apparatus employing a fragile film, and which, if the strong or the direction of travel of the of the drivin normal film continues'to be used, will assure a great'redu'ction inthe wear of the film-and mechanism.. 4

I may emp oy analogous constructions for the Idoor with variable ressure. Fi 7 shows a modification in w ich the sha t 24 controlling the pressing elementsv may slide lengthwise, and' parallel with the hinge, or more generally,in a directionl arallel with m, I prefer this disposition in cases in which the door as mounted on the hinges of the door, so that is not 'hinged I,but is moved parallel with the main art of the guideway (i. e. a vertical- -ly sli ing door orjthe like In this event, -if the shaft 24 does not coincide with the axis of the hinge, the cams 25 '(or the levers) `controlling the transmission shafts mounted on the door, should be provided with the ramps 26|w'hereb the corresponding ca'ms will not be held ast when the door is closed.

In principle, this part of my said inven-` tion consists of a door provided with pressing elements which are controlled by power transmission means which maybe wholly or partially mounted upon the said door, which means may be controlled by the parts coacting with` the mechanism of the apparatus, and whose supports `are preferably the `whole device may be'mounted as a whole and without requiring any adjustment, upon a known cinematographic apparatus.

It maybe advantageous, in order to maintain the film flat in more approved condii tions, to combine the present invention with my prior` invention, the subject-matter of. l. the patentv application No.l 200,253, .tiled `June 20, 1927, entitled: Improvements in cinematographicfapparatus in which I uti- ,lizea current of 4air to apply 'the film against the wall of the guideway. I may further utilize plates of a rigid and ltrans arent l"subrstance which are l actuatedvr by t e. driving `,mechanism and will pressin-a periodic manner upon the film so as to apply it against a stationary in the apparatus.

Having thus described my apparatus, what l I claim as new therein, and my own invention, is:

1. In a cinematogra hic apparatus utiliz-` ing a fiexible film, t ez combination of' a guideway adapted toguide the said ilm,a

transparent surface comprised pushing element adapted to maintain the said film in the said guideway and controlling means for periodically pressing and raising4 the said pushing element, the period of pressure offthe said element corresponding to the stopping, of the said film and the period of raising corresponding tothe displacement-of the said film, the said control- 1 ng means being connected with the mechanism of the apparatus, a second pushing element adapted to exert a constant and slight pressure on the said film, a movable door adapted to close the said guideway and to support the first and the second pushing element and also the said controlling means.

2. In a -cinematographic apparatus utiliztrolling means being connected with the' mechanismof the apparatus, a second pushin g element adapted to exert a constant and slight pressure 'on' the said film, a movable door adapted to close the said guideway and to support the first and the second pushing element and also the said controlling means, the pivoting axle of the said door being adapted to constitute the shaft for transmitting the motion to the said pushing elements mounted on the said door.

In testimony whereof I have hereunto aiixed my signature.

ETIENNE oEHMIcHEN. 

